Identification of S sub(6) and S sub(7) sulphur allotropes in trophosome of Riftia pachyptila (Vestimentifera) from Hydrothermal vents

The two sulphur allotropes S sub(6) and S sub(7) were characterised by gas chromatography/mass spectrometry coupling experiments in trophosomes of Riftia pachyptila (Vestimentifera), which inhabit hydrothermal vents. Both allotropes (approximately 3% for both) are associated with the usual form S sub(8) that represents about 97% of the total sulphur fraction. These new natural varieties of sulphur could be due to bacterial oxidation of hydrogen sulphide in extreme conditions (about 300 kg cm- super(2)). However, the occurrence of the same allotropes in mineral sulphur from different origin, terrestrial and extraterrestrial as well, could indicate that natural sulphur is a mixture of these three allotropes, with proportions depending on its geographical origin.Original Abstract: Les varietes allotropiques S sub(6) et S sub(7) du soufre elementaire ont ete identifiees a l'aide du couplage chromatographie gazeuse/spectrometrie de masse, dans les trophosomes du vestimentifere Riftia pachyptila. Ces deux allotropes representent un peu moins de 3% du soufre total, qui se presente majoritairement sous la forme normale S sub(8). L'oxydation bacterienne de l'hydrogene sulfure dans les conditions extremes qui regnent au voisinage des sources hydrothermales sous-marines (environ 300 kg cm- super(2)) pourrait justifier la formation de ces varietes de soufre. Cependant, la presence de ces memes allotropes dans des echantillons de soufre d'origine minerale, terrestre et extraterrestre, pourrait indiquer que le soufre naturel est un melange de ces trois allotropes, dans des proportions qui dependent de l'origine de cet element.